This application relates to a ventilation manifold having a variable cross-sectional flow area across a circumference of an associated engine.
Gas turbine engines are known and, typically, include a fan delivering air into a bypass duct. The bypass duct is defined outwardly of a core housing. The core housing has an upstream end, typically, known as a nacelle. Cooling air may be supplied within the core housing and across various accessories that are positioned within the core housing. As an example, various fluid components must be cooled. Also, an accessory gearbox may be positioned within the housing and must be cooled.
An inner core housing houses a compressor, a combustor and a turbine section. The amount of air delivered into the bypass duct provides a propulsion flow in addition to an exhaust power downstream of the core engine and which powers an associated aircraft.
The cooling air moving inwardly of the nacelle may be tapped from the bypass flow and, thus, the volume tapped reduces the efficiency or amount of propulsion provided for a given amount of fuel being burned. It is, of course, desirable to increase the efficiency.
The cooling load is not uniform across a circumference of the interior of the nacelle. Moreover, the volume of air distributed into the nacelle at locations closer to an inlet will be greater.
In known manifolds, the flow area has typically been uniform across the circumference of the engine.